When non-removable is used for emmc,  MMC_CAP_NONREMOVABLE should
also be checked, otherwise detection fail since present=0

Signed-off-by: Zhangfei Gao <zhangfei.gao@linaro.org>
Signed-off-by: Jaehoon Chung <jh80.chung@samsung.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>